Tension device.



Patented June 4, 1912.

B. I'. MAYO.

TENSION DEVICE.

APPLICATION HLBD Nov. 22, 1909.

' Patented June 4,1912'.

2 SHEETS-SHEET 2.

entran sra'rns gParma caricia.

BENJAMIN E. MAYO, OF SALEM, MASSACHUSETTS, ASSIGNOR TO UNITED SHOE MACHINERY; COMPANY, OF PATERSON, NEUV JERSEY, A. CORPORATION OE NEW JERSEY.

TENSION DEVICE.

vTo all lwhom t may concern:

Be it known that I, BENJAMIN F. MAYO, a citizen of the United States, residing at Salem, in the county of 4Essex and AState of Massachusetts, have invented certain new and useful Improvements in Tension Devices; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will -enable others skilled in the art to which it appertains to make` and use the same.

l The present invention' relates to an iinproved tension device particularly adapted for use on wax-thread shoe-sewing machines which form a chain-stitch, although the invention is capable ofnse on other types of sewing machines. l

In chain-stitch shoe-sewing machines it hasI been proposed to use a tension device or devices which are so actuated as to exert one tension on the thread at one point in the cycle otoperat-ions of the machine in forming a stitch and to exert another tension on the thread at another point'in the cycle of operations. Thus in a chain-stitch shoesewing machine provided with a take-up operating while the needle is in the work, a

tension device has been used which exerts a comparatively light tension on the thread during the loop drawing stroke of the needle and a comparatively heavy tension on the thread during the stitch setting stroke of the take-up. This tension device has embodied two brakes and two separate springs for actuating the brakes, one brake being in operation constantly and the other brake being thrown out of operation during the loop drawing stroke of the needle. This forni ot tension device has given more or less trouble by reasonl of the fact that in order to adjust the tension device so as to produce Athe best results on a givenvclass of work, an ad justinent of both springs has been necessary. As a consequence, an operator often adjusts one or both springs improperly so that .y either the heavy or the light tension ,is not tof the required amount, and the required ratio between thetwo tensions is not preserved.'

The principal object of the present invention is to provide a tension device which can be actuated to exert di-i'erent degree-s of ten' sion on the thread at different-.times during l Specification-of Letters Patent.

the stitch formingoperation and which can be readily adjusted without liability of changing, to an Yobjectionable extent, the required ratio between the4 tensions.

Other objects of the invention are to provide a tension device the parts of which are constructed and arranged to operate in an improved manner. y

With the above objects 1n view a feature vof the present invention contemplates the .while the tension on the thread at all times is due to the force exerted by a single spring. The tension on this spring can be adjusted and thus the amount of the tension exerted on the thread at all times during the forma,- tion of a stitch uniformly increased or diminished. The tension device can theretore be adjusted'by a single adjusting de vice and the required amount of tension on the thread at any period in the cycle of operations secured without disturbing to an objectionable extent the proportions of the different tensions. In accordance with this feature of the linvent-ion the connections between thespring and the brake mechanism may be constructed, arranged and actuated in any suitable manner. In the preferred form of the invention hereinafter described, however, two sets of connections are provided between the spring and t-he brake mechanism and means are provided for throwing one set of connections out 4of operation during each cycle of operations ot the brake mechanism comprises two brakes,

and a single spring is provided for actuating both brakes, so thatv the pressure'of th brakes can be adjusted simultaneously b; a

Patented June 4, 1912. i Application led November 22, 1909. 'Serial'Na 529,342.

, formation of a stitch.

sists in certain devices, combinations and arrearA view of 'the mechanism` illu'strated'in French & Meyer, No. 412,704, although many brake and consequently-the tension produced Asoas to change the tension on the thread without changing the ytension of the spring 4vention will be clearly understood from an Which- 4welt sewing machine of the same general arranged. lThe hooked-needle of thema- -in substantially the same manner as in `the single adjusting means. This construction constitutes a feature ofthe present invention which broadly considered is not limited to a construction' 'embodying' a single springv since it isibelieved to be new in a tensionv device comprisingtwo brakes to provide means for simultaneously adjusting the ressure of both brakes together with means or throwing one brake out of loperation during each cycle of operations of the machine.

'In the construction hereinafter described as embodying the preferred' `form of vthe present invention, adjusting'means are pro-v vided between the spring and one of t-he brakes whereby the pressure exerted by the on the thread can be' adjusted Without changing the tension of the spring. It is believed to'be new in a tension device to provide lmeans for adjusting the devices which are actuated by the spring toproduce tension and such a construction constitutes a feature of the present invention which is not limited to use in' a vtension device adaptechto exert dierent tensions on the thread during the.

In addition to the features of invention referred to the present inventionalso conran'gements of parts, the advantages of vwhich will be obvious to those skilled in the art from the following description.

Thev several features of the present in# inspection-of the accompanying drawings in Figure 1 is a view in side elevation partly in section of a chain-stitch shoe-sewing machine, with a tension device embodying the invention in its preferred /form applied -Fig. 2 is a view in side elevation of the tension device looking in the opposite direction from Fig.` 1 and Fig. 3 is a- Fig. 2. The sewing -machine illustrated 1n the drawings, is a chain-stitch hooked-needlev type as thatidisclosed in the patent to of the parts and their actuating mechanisml are somewhat differently constructed and chine operates to draw loops of `thread through the work and the take-up of the 1nachine acts to l exert a stitch setting strain on-the seam while the needle is in the work,

machine of the patent above referred to. In the patentedmaehine, a uniform tension is exerted lupon the thread at alltimes, while inthe machinel illustrated in thedrawings of thisapnlication 'a -compznatively light tension is inserted on the thread rduring the loop draw-ing stroke of the needle, and af, comparatively heavy tension during the `stitch setting stroke of the take-up.

Referring now to the drawings, 1 indicates the curved hook needle of the machine, L

2 the needle guide, 3 the looper, 4; the thread` arm, 5 the take-up, 6the auxiliary take-up,

7r the welt guide and 8 the back rest. The

specific construction and arrangement of these parts isimmaterial Vso far as the present invention is concerned and conse-' quently no further description of them will lever 15 pivoted at 16 on the bracket. The 'brake shoes are oppositely disposed with relation to eachnother so as to engage op-v posite sides of the drums 9 and 10, and both levers are acted upon by a single spring 17 which tends to move the levers in a direction to press the brake shoes against theirI cooperating drums'. To permit the spring 17 to act ou both levers 13 and 15, a rod 18'is provided which is pivotallyconnected to the lever 15 and which extends 'transversely of the lever 13 through a slot in thev tion. The drums D and 10 are fast upon the shaft which carries the usualthread tension truck 20 so that the tension on the thread is determined by the pressure of the brake shoes 11 and 12 on the drums. At certain times during' each cycle of operations of the machine, therefore, the tension on the thread is produced by the engagement of the brake shoevll with the drum l9, 'while at other times the tension on the thread is produced by the engagement of both brake shoes with their Cooperating drums. The Aamolnt ot' each of these tensions can be adjusted by adjusting nuts 19,'an adjustment of the tension of the .9 until the completion of the sewing operaspring increasing or decreasing the pressure exerted by each brake shoe on its drum. Both of the tensions which are produced upon Vthe thread can thus be readily adjusted without any liability of changing to an injurious extent therelative proportions of the two tensions.

In addition to the means above described lfor adjusting the amount of tension produced upon the thread, the tension device illustrated in the drawings is so constructed that the amount of-the tension produced on the thread can be adjusted without changing the tension of the spring 17. To secure this result t-he rod 18 is so mounted that it can be swung about its pivot toward and from the pivot lll of the lever 13 to move the point of application of the spring 17 nearer to or farther away from the fulcrum of the lever. To hold the rod in adjusted posi tion a collar 21 is loosely mounted upon the rod between the spring 17 and the lever 13 and is provided with'teeth arranged to engage a series of teeth on the lever. An adjustnfient of the rod 18 about its pivot varies the pressure eXerte f by the brake shoe 11 on the drum 9 and changes the proportions of the two tensions produced upon t'he thread as 'well as the amounts of such tensions.

The const-ruetion illustrated in the drawings for raising the brake shoe 12 out of engagement with the drum 10 during each cycle of ,operations ofthe machine consists ofa cam actuated bell crank lever 22 and a lever 23, the upper end of`which is engaged by the bell crank lever 22 and the lower end of which engages a'pin 24 projecting latbrake shoe 12. During the operation of the machine the bell crank lever 22 is actuated to hold the brake shoe 12 out of engagement with the drum 10 during thfex retracting stroke of the needle and to allow the brake shoe tobein engagement with the drum 'during the stitch setting stroke of the takeuP- i i To prevent any substantial increase in the tension of the spring 17 when the lever 15 isf-actuated to move the brake shoew12 out of 'engagement with the drum 10, the rod 18 is'pivotally connected tothe lever 15 at a comparatively short distance from the pivot of the lever, and to secure the requiredbrakingeifect of the'brake shoe` 12, the drum 10 is preferably made larger than the drum 9.

` The machine illustrated in the drawings is provided with means for relieving the yten/sion on the thread to allow the removal of {lt-,he work at the end of the sewing operation The tension releasing mechanism is e? 4actuated by a reversal in the direction of roi'ation of the driving shaft 25 of the mahine, tand includes an arm 26 similar vto j yhat used 1n tension releasing mechanism eretofore devised, which arm is provided with two surfaces 27 and 28 at different dise-rally from the lower end of the lever This pin also serves as the pivot for the tances from the pivot 29 of the lever. The surfaces 27 and 28 are arranged to bear against a collar 30 on the driving shaft 25 and between the surfaces is a projection 31 adapted to enter a recess 32 when the direction of rotation of the driving shaft is reversed. When the driving shaft is running in a forward direction the surface 27 is in engagement with the collar 30 indicated in F ig. 2. Upon a reversal in a direction of rotation of the driving shaft at the end of the sewing operation the recess 32 engages the projection 31 and the arm 2G is swung to bring the surface 28 into engagement with the collar. This swinging movement of the arm 26. also moves the arm longitudinally by reason of the fact that the surface 28 is at a greater distance from the pivot 29 than the surface 27. The arm. 2G is pivoted at 29 upon the upper end of a bell crank 33. To the horizontal arm of the bell crank 33 is pivotally connected the npper end of a vertical rod 34.` which is provided with a shoulder 35 arranged to engage the upper surface of a horizontal arm 36 extending from the hub of thebrake carrying lever 13. An oscillation of the bell crank 33 produced by a reversal in the di rection of rotation of the driving shaft 25 moves the rod 34 downwardly and actuates the arm 36 -and lever 13 so as to move the brake shoe 11 out of vengagement with the drum 9. rI he cam onfthe driving shaft 25 which actuates the bell crank lever 22 is so arranged that at the time "the arm 2G is swung by the backward/rotation of the drive ing shaft the bell crank 22 is actuated to raise the brake shoe 12 'out of engagement with the drum 10. A reversal in the direction of rotation of the driving shaft therefore throws bot-h shoes out of operation and releases the tension on the thread. The machine illustrated in the dra-wings is also provided with means for retracting the welt guide when the thread is relieved of tension. This means consists of'a bell crank v37, the horizontal arm 'offwhich projects Aare similar to mechanisms which have heretofore been devised and have been illustrated in the drawings of the present application merely for the purpose oshowing a complete tension device embo ying the features of the present invention.

The nature and yscope of the present invention having' beenmdicated and a preferred form ofthe invention having been specifically describedwhat I claim is 1. A sewing-machine, having, in combination, stitch formingdevices, a tension de- `vice including a'brakc mechanism, a spring 2. lA sewing machine, having, in combination, stitch forming devices, a'tensilon 'device including a brake mechanism, a spring and two sets of connections between theA spring and brake mechanism and means for' throwing one set oni of connections. outof.

operation during eac cycle of operatins of.

- the machine.

s lever.`

3. A sewing machine, having, in coInloi-gl nation, stitch forming devices, a 'tension-dew vice including a brake, a brake carrying lever, a., spring arranged to act on the lever, a rod for supporting the spring arranged transverselyof the lever and ymovable to 'ad-.- just the point at which the spring actsfon the lever with relation to the-fulcrum ofthe.

4. A sewingmachine, having, in combination, stitch forming devices, a tensionvdevice including' two oppositelyv disposed brakes, an actuating lever foreach brake, a' spring acting on both levers, and means `for.. throwing one brake only .out of operation during "each cycle of operations of the ma'- chine.

5. A sewing machine, having, in combination, stitch forming devices, a tension dev-lce including two oppositely dlsposed brakes, an actuating lever foreach brake, a

rod connected to onelevcr and extending transversely of the other lever, a spring sljpported by said-rod arranged to'actuate both y ations of themachine. f

levers, and means for throwing one brake out of operation during each cycle of oper- (i. A'sewingmachine, having, in combi-.

' nation, stitch forming devices, avtension de- Operations or' the machine.

1riceincluding two brake disks of different sizes, a brake acting on thc peripheral sur'- face of each disk, and means for moving one brake out. of engagement with its disk durin each cycle of operations ol the machine.

A' sewing machine, having, in combination, stitch forming devices, a tensiondevice including two brakes, a single adjusting means for adjusting the pressure of both .brakes, and means for throwing one brake -v lonly out of operation yduring each cycle of' nationjstitch forming devices, a tension vfie-- vice including twobrakes, means for simultaneously A'adjusting the pressure of bothk` only out dfy operatioii operations of the madhine. Y

9.-A sew-ing machine,having, in 4combinati'n, stitch .forming devices, a tension de brakes, means for adjusting the pressure of one brake independently of the other, and

ation during each cycle machine.

atirigboth brakes and means for throwing one brake onlyout ofpera'tion during each cycle of operations of the machine.

1t.- A sewing machine, having, in combi` and two s ring van Ybrake mechanism means v tilrowing lone 'set of 'connections out of operation during each cycle of operations of the stitchfsettingstroke of the take-up, a Single of both tensions ,and means lforl adjusting they amount of onetension independently of theother. j' 13. vA chain stitch sewing machine, having,v in combination stitch ormin including atake-up acting while t e needle is in the work, a tension device, -means'for actuating said Vdevice to exert a relatively light tension onthe thread during the' loop drawing; stroke ofv the needle and a relaf tively heavy tension` on the stitch Vsetting stroke of the take-up, 'means amount of both tensions 4and meansforad-` justing the amount of one tension independently of the other. f "l f. BENJAMIN F. MAYO. Witnesses: V- y WARREN G. OGDEN,

FRED IO. FisH. I

' means for throwing one brake out of oper-2l of' operations of the 8. A sewing machine, having, incombi-v 'j brakes and means fodthrowing one brake "j, uring each cycle'f ref;

vicey'including two brakes, meansjor simul'- n taneously adjusting `the pressureof both for simultaneously adjusting the@ "nation,stitchLtiirming-devices, a tension de- ,vice, including-a brake mechanism, a 'spi'flnlgy ets of connections between-tf-he or machine, and means'foradju'st-ing the-pres-A sure produced by one set offconnections in- 'dependent-ly of 'that produced. bythe otherv adjustngmeans for 'adjustingkth'e amount the thread. during i 10.k A sewing machine, having,.in combi-,Q80 nation, stitch forming devices, a tension'de? vice including two brakes, a spring for actu- 

